Motion estimation (ME) in high-definition H.264 video coding presents a significant design challenge for memory bandwidth, latency, and cost because of its large search range and various modes. To conquer this problem, this paper presents a low-latency and hardware-efficient ME design with three design techniques. The first technique on integer-pel ME (IME) adopts parallel instead of serial multiresolution search so that we can process 1080 p @ 60 fps videos with plusmn128 search range within just 256 cycles, 5.95-KB buffers, and 213.7 K gates. The second technique on fractional-pel ME (FME) uses a single-iteration six-point search to reduce the cycle count by half with similar gate count and negligible quality loss. The third technique applies a mode-filtering approach to further reduce the bandwidth and cycles and share the buffer of IME and FME. The final ME implementation with 0.13-mum process can support processing of 1080 p @ 60 fps with just 128.8 MHz, 282.6 K gates, and 8.54-KB buffer, which saves 60% gate count, and 68.9% SRAM buffers when compared with the previous design.

https://ir.nctu.edu.tw:443/bitstream/11536/8606/1/000257711600013.pdf

A Hardware-Efficient H.264/AVC Motion-Estimation Design for High-Definition Video

Managing the complexity of the emerging HEVC standard is a matter of academic and industrial research since its earlier versions The sophisticated and computation-intensive tools involved in the encoding process must be leveraged if real-time applications are considered In this paper, we propose a workload management scheme for dynamically controlling the computational complexity of HEVC, under user-defined operation frequency and target FPS Our scheme receives these two parameters as input and aims to meet the target FPS by adjusting different encoding parameters during execution time Experiments demonstrate that our scheme successfully meets the target FPS while introducing negligible rate-distortion losses A comparison with state-of-the-art shows that our scheme is capable of achieving a time reduction of up to 43% for Full HD sequences, with a maximum loss of 003 dB in Y-PSNR and a 35% increase in bitrate

An adaptive workload management scheme for HEVC encoding

The next generation video coding standard, namely HEVC(High Efficiency Video Coding) introduced many efficient algorithms to enhance the coding efficiency. However, the computational complexity of motion estimation is still the most bottle neck for its implementation. In this paper, we propose a complexity reduction algorithm for fractional-pixel motion estimation (FPME). Firstly, a fast termination algorithm is proposed to fast terminate FPME using a threshold. Next, the proposed algorithm designs several original search orders and search patterns for 1/2 pixel and 1/4 pixel motion estimation, respectively. These proposed patterns are on the basis of the probability of each search point and its surrounding integer search points. Simulation result shows that the proposed algorithm succeed in reduction of search point for up to 38% with almost no coding efficiency loss.

Low complexity algorithm for sub-pixel motion estimation of HEVC

Quad-tree based Coding Unit structure in HEVC provides more motion compensation sizes to improve rate-distortion performance at the cost of greatly increased computational complexity Different from other researches on fast algorithms, we develop an optimally complexity scalable multi-mode decision algorithm (OCSMD) for HEVC There are two major contributions in this paper The first one is a novel feature proposed to describe the relationship between MV field and CU depth The second is that we build a cost-performance priority predicting model in frame level based on the feature with negligible overhead as well as no conflict with the standard Our method may allocate computational resources to the MD of all the CUs in frame level under arbitrary complexity constraints, while obtaining nearly optimal coding performance The experimental result shows that our algorithm can adjust complexity under varying computing capacity while achieving near-optimal R-D performance

An optimally complexity scalable multi-mode decision algorithm for HEVC

Fractional-pixel motion compensation is still one of the most time-consuming parts in the upcoming High Efficiency Video Coding (HEVC) standard. In this paper, we propose an optimally scalable and cost-effective fractional-pixel motion estimation (FPME) algorithm to optimally fit to different and varying constrains of computing resources. Our main contribution include two aspects. Firstly, an optimally scalable and cost-effective FPME algorithm based on a cost-benefit analysis is proposed, where we present a improved fractional-pixel MV prediction method and a new cost-effective priority for each search point in HEVC. Secondly, a complexity adjustment strategy is delivered to enable the ability for the FPME to adjust its complexity to match different given constraints on time. Experiments show that the proposed algorithm can achieve best R-D performance while optimally adjust its complexity, based on any given time constraints. As a side product, the proposed algorithm can also serve as the best fast algorithm which has already reduced computing complexity by a factor 74% with almost no loss on PSNR and bitrates.

An optimally scalable and cost-effective fractional-pixel motion estimation algorithm for HEVC

The additional complexity of the adoption of fractional-pixel motion compensation technology arises from two aspects: fractional-pixel interpolation (FPI) and fractional-pixel motion estimation (FPME). Different from current fast algorithms, we use the internal link between FPME and FPI as a factor in considering optimization by integrally manipulating them rather than attempting to speed them up separately. In this paper, a refinement search order for FPME is proposed to satisfy the criteria of cost/performance efficiency. And then, some strategies, i.e., FPME skipping, early termination and search pattern pruning, are also given for reducing the number of search positions with negligible coding loss. We also propose a FPI algorithm to save redundant interpolation as well as reduce duplicate calculation. Experimental results show that our integrated algorithm significantly improves the overall speed of FPME and FPI. Compared with the FFPS+XFPI and CBFPS+XFPI, the proposed algorithm has already reduced the speed by a factor of 65% and 32%. Additionally, our FPI algorithm can be used to cooperate with any fast FPME algorithms to greatly reduce the computational time of FPI.

On Combining Fractional-Pixel Interpolation and Motion Estimation: A Cost-Effective Approach

In this paper, we proposed a new fractional pixel motion estimation method that effectively extends predictor based algorithm for integer pixel search to fractional pixel search. It generates very precise predictors and makes use of simple refinement patterns in successive search. According to our experiments, the proposed method not only has superior speed compared with other methods, but also produces the same PSNR as full fractional pixel search (FFPS) for all block modes of H.264. However, current fast fractional pixel search methods adopted by H.264 JM do not guarantee the same search quality as FFPS in different block mode.

A High Accurate Predictor Based Fractional Pixel Search for H.264

To deploy highly efficient video coding technologies on different hardware platform, complexity adjustable algorithms are required. One of the significant resource consumers is motion estimation (ME). This paper proposes a complexity adjustable algorithm for ME to remedy this issue. First, we build a mathematic model to indicate that macroblocks (MBs) with intensive motion are worthier of finer searching than other MBs. And then, under a specified computational restriction, a principal is delivered to determine what kinds of MBs should be thoroughly searched prior to others. According to our experimental results, the proposed algorithm not only freely adjusts the complexity for ME but also attains much higher speed without any coding loss than using fast ME algorithms along. Our algorithm, with complexity scalability, can be easily used on platforms with varied computational capabilities. Also, the algorithm allow us dynamically choose different ME strategies to meet the need for the optimal balance between distortion gain and computational complexity.

A complexity adjustable algorithm for motion estimation in H.264

The invention provides a joint fractional point motion evaluation and interpolation method for H.264 video coding, comprising the following steps: 1) a cost performance ratio preferential motion evaluation method: dividing a searching area of the fractional point motion evaluation into four groups, determining the cost performance ratio priorities of each group from the highest to the lowest, performing the fractional point motion evaluation according to the sequence of the cost performance ratio priorities, checking the values of the fractional points with the high priorities firstly, then checking the values of the fractional points with the low priorities, and checking according to the clockwise direction when the searching points having the same priority exist; and 2) a cost performance ratio preferential interpolation method: grouping according to the cost performance ratio priorities and performing interpolation in the interpolation operation of the fractional points.

Joint fractional point motion evaluation and interpolation method for H.264 video coding

Extended macroblock size (EMS) improves the highest possible coding efficiency for the current video coding standards, but a large number of additional candidate coding modes results in high computational expense. In this paper, the correlation among different modes is exploited to drastically reduce the number of candidate modes in EMS. And a fast inter-mode decision algorithm for EMS is proposed based on above facts. Furthermore, a split and merge technology is used to find the optimal partitioning with computational efficiency. Experimental results show that the proposed fast inter-mode decision algorithm reduces the computational complexity significantly with negligible coding lost. 1

Jiyuan Lu

Papers

On Combining Fractional-Pixel Interpolation and Motion Estimation: A Cost-Effective Approach

A High Accurate Predictor Based Fractional Pixel Search for H.264

A complexity adjustable algorithm for motion estimation in H.264

Joint fractional point motion evaluation and interpolation method for H.264 video coding

A split and merge algorithm for inter-mode decision in extended macroblocks